Method of cutting diamonds.



'Nn. 694,2l5.

J. H. G.-.STUUBMAN. METHOD OF CUTTING DIAMONDS.

(No Model.)

(A umeion med Dec. 5, 1901.

Patented Feb. 25, I902- Witnesses ,me Noam; Pucns co. warn-undo" wnsumcrcma. Q

UNITE STATES PATENT FFICE.

JOHN H. G. STUURMAN, OF BROOKLYN, NElV YORK, ASSIGNOR OF ONE- IIALF TO HERMANA. GROEN AND JOSEPH GROEN, OF NEWV YORK, N. Y.

METHOD OF CUTTING DIAMONDS.

SPECIFICATION forming part Of Letters Patent N0. 694,215, dated February 25, 1902.

Application filed December 5, 1901. Serial No. 84,859. (No specimens.)

To all whom, it may concern: parts. Fig. 6 is a side elevation of a diamond Be it known that I, JOHN H. G. STUURMAN, afterthe cutting and cleaning operations have a citizen of the United States, residing at been completed. Fig. 7isaperspective view Brooklyn, in the county of Kings and State of one of the parts of the stone after having 55 of New York, have invented new and useful been divided and the edges cut off.

Improvements in Methods of Cutting Dia- In the drawings I have illustrated convenmonds, of which the following is a specificationally a mechanism for carrying out the tion. method forming the subject-matter of my in- In shaping or, as it is technically called, vention, and reference being had to the illus- 6o :0 cutting diamonds it has been the practice trations it will be perceived that in forming prior to my invention to subject the stone to the divisional cut a disk-shaped cutter 10 is a grinding process, which, because of the exemployed, which is about as thick as ordinary treme hardness of the stone, is very slow and writing-paper and may be made of suitable tedious and greatly increases the cost of prosteel. This cutter is mounted upon an arbor I 5 duction of the finished article. The most seor shaft 11 and braced by collars 12, arranged rious drawback to the usual process, howon opposite sides thereof and suitably fasever, resides in the fact that a very material tened to the shaft. The shaft is rotated by part of the diamond is reduced to'dust or meansofamotor-actuated bandor belt, which powder, which, while useful for grinding purmay be mounted on a pulley 13 on the shaft.

2o poses, is of very low and trifling value as com It will be premised that, so far asI am aware,

pared with the original value of the portion prior to my invention it was deemed practireduced by attrition. call yimpossible to cutor saw directly through It is the object of the present invention to the thicker portion of the stone; but by my overcome and do away with this grinding invention it has been proven practical, expe- 7 5 2 5 process in the primary preparation of the diaclient, and successful. This difficulty I overmond and practically save all the diamond come primarily by abrading or roughening a by severing or dividing it into two halves or point common to the angle of intersection of sections substantially equal in size, weight, the girdles, as indicated at a, to afiord an enand value. This I accomplish by cutting entrance or start for the saw or cutter to engage 8o o tirely through the stone on the line with either preliminary to its progress through the stone. of its axes, beginning atone of the points of This abrasion may be accomplished by any i intersection of the girdles and continuing the of the means well known in the trade, usually 3 out directly on the line of the selected axis by rubbing the point with a diamond-chip. until the stone is divided. It is to be understood that the diamond (in- 35 In order to illustrate the manner of carrydicated at 14) is to be held firmly by means of ingoutthe method embodied in myinvention, a chuck or any suitable form of holder, the reference is made to the accompanying draw diamond being arranged and adjusted so as ings, whereinto present one of the points at the intersec- Figure 1 is aview in elevation of a convention of the girdles directly in line with the 4o tional cutter, its shaft, and driving-pulley, cutting edge of the disk and one of the axes also indicating a diamond placed in proper of the stone also directly in line therewith. position for contact with the cutter and be- As above stated, the diamond is subjected to ginning of the out. Fig. 2 is an enlarged fragthe action of the cutter by presenting thereto lnentary side elevation of the cutter, also repone of the points at the intersection of the 45 resentingadiamond as being presented to the girdles, said point having been first roughaction of the cutter. Fig. 3 is a view of a diaened or abraded, as indicated in Figs. 1 and mond preparatory to being cut in two. Fig. 4: at a, and with one of its axes in alinement t is a View showing the diamond-point as with the cutter. Any suitable feeding mechabraded for engagement with the cutter. Fig. anisrn may be utilized for advancing the dialoo 0 5 is a View showing the sections or halves afmond toward the axes of rotation of the cutter the diamond has been divided into two ter, so to cause the cutter to Work its Way through the diamond. The divisional cut is made directly in line with and in the plane of the selected axis, so that after the cutter has worked its way entirely through the diamond the stone is divided into two equal parts, as indicated by 16 17 in Fig. 5 of the drawings. These parts or sections are substantial counterparts of each other, and each is substantially one-half the weight of the original stone, since owing to the thinness of the cutter there has been practically no waste. After accomplishing the division of the diamond each of the parts'is subsequently subjected to the action of the splitting-tool, and the sides and ends bordering the table of the diamond are removed, as shown in Figs. 6 and 7, thereby forming the facets 18, bordering the newly-formed table 20. The small particles which are split from the sections to form the facets 18 may be utilized in the manufacture of glass-cutters, drills, and other cutting instruments in which diamond cutting-points are ordinarily employed.

From the foregoing description it will be ascertained that practically all of the diamond is preserved instead of reducing a material portion of the original stone to dust or powder.

Vhat I claim is 1. The method of cutting through the axis of a diamond herein described, consisting in abradingthe diamond at a point of intersection of the girdles, and then continuing the cut through the selected aXis of the stone at right angles to its other axis, substantially as specified.

2. The method of cutting through the axis of diamonds to divide them in two equal parts herein described, consisting in abrading the stone at a point of the intersection of the girdles, and then making a dividing cut directly on the line of the selected axis of the stone, whereby the stone is divided into two equal parts, and then splitting off the points, sides and ends, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN H. G. STUURMAN.

Witnesses:

SIMON GRonN, JAooUEs U. PIMENTER. 

